File Comparison using Shell Programming

Question

Hi All,
I want to compare two text files using shell programming. The two text files are actually Business Objects output extracted in a text format. The two output files are not in a tabular format and are no way similar in looking. I want to take one file e.g. file1 as an input file and compare each line of file1 with the other file e.g. file2. During comparison I want to extract the differences found in another file and if possible the similar data as well.
Below is how the files will look like
File 1:
BILL1000000 1111251 122222
RMG1A2 023425100000000010001 11135 102650111100
UHL1 6999999 454540001 Weekly 000
0544424556895PS DATA 01MPS100000/03 MR A A PERTH UTL1234567893106923455053106900000010000005
File 2:
AUTO
APPLICATION=STARTPOINT
START
PROCESSING DATE=01012011
1598301270320099TEST C E 00000031615 123456
7854301276140499TES P 00000062943 234567
UHL1 6999999 454540001 Weekly 000
5569931233333499/123456789 00000013396 345678
4471931233333499ER K J 00000031835123456789012456789
33652931233333499E J L 00000034729123456789012567890
45783123333349921/123456789 00000039080 678901
1452931233333499T R 00000040678123456789012789012
59689312333334994/987654321 00000048614 890123
4112931233333499/987654321 00000060631 901234
1236931217836899 K S 00000043704 012345
END
As you can see above the file are not at all matching except for one record UHL1, but its just an example. As an output I would like to have a third file containing all these records, highlighting the differences, and a fourth file where in only the matched records should get populated.
Please post any useful scripts related to the above scenario.
Many Thanks.

Answer 1

Nik,
Thanks for that script. Its solving my purpose upto an extent.
Going another level to that example, in cases where in the first column of file 1 is to be compared with second or third column in file 2, what all the changes should be made to your script. For example,
File 1:
1       a       APPLICATION=WWAGES      8       9
2       b       1200301270320099TEST  C E         00000031615            123456
3       c       1200301276140499TES  P            00000062943            234567
4       d       APPLICATION=WWAGES      6       7
5       e       1200301270320099TEST  C E         00000031615            123456
6       f       1200301276140499TES  P            00000062943            234567
7       g       APPLICATION=WWAGES      4       5
8       h       1200301270320099TEST  C E         00000031615            123456
9       i       1200301276140499TES  P            00000062943            234567
10      j       APPLICATION=WWAGES      2       3
11      k       1200301270320099TEST  C E         00000031615            123456
12      l       1200301276140499TES  P            00000062943            234567
File 2:
a       1       APPLICATION=WWAGES      8       9
b       2       1200301270320099TEST  C E         00000031615            123456
g       7       APPLICATION=WWAGES      4       5
h       8       11200301270320099TEST  C E         00000031615            12223456
k       12      1200301276140499TES  P            00000062943            234567Now, in the above example First and Second Columns of File 1 are to be compared against Second and First Columns of File 2 respectively. Please see that in file 2, 12 and K are not matching with file1's record 11 and K, so they should not be picked.
Based on the matched columns, will continue comparing rest of the fields for the records.
Please guide me the changes to be done in your script for catering to the above scenario.
Thanks.